Enzymatic and metabolic evidence for a region specific mitochondrial dysfunction in brains of murine succinic semialdehyde dehydrogenase deficiency (Aldh5a1-/- mice)

Neurochem Int. 2007 Mar;50(4):653-9. doi: 10.1016/j.neuint.2006.12.009. Epub 2007 Jan 13.


Succinic semialdehyde dehydrogenase deficiency, a rare inherited defect of gamma-aminobutyrate (GABA) catabolism, presents with characteristic biochemical abnormalities in the central nervous system (CNS). These include elevated concentrations of GABA, gamma-hydroxybutyrate (GHB), succinic semialdehyde (SSA), 4,5-dihydroxyhexanoic acid (DHHA) and alanine as well as decreased concentrations of glutamine. GABA degradation is coupled to Krebs cycle function in mammalian CNS ("GABA shunt") through succinate and alpha-ketoglutarate. Accordingly, we hypothesized that disruption of Krebs cycle and respiratory chain function in the CNS is involved in the neuropathogenesis of this disease. For this purpose, we investigated cerebral activities of Krebs cycle and respiratory chain enzymes as well as the glutathione content in Aldh5a1(-/-) mice, a recently generated mouse model for this disease. In CNS tissue of Aldh5a1(-/-) mice, we found a significantly decreased glutathione content (hippocampus, cortex) and decreased activities of complexes I-IV (hippocampus) suggesting increased oxidative stress and mitochondrial dysfunction. However, specific activities of Krebs cycle and respiratory chain were not affected by GABA, GHB, SSA, or DHHA (up to 1 mmol/L). Although our results suggest hippocampal and cortical dysfunction in Aldh5a1(-/-) brain, we found no evidence that accumulating key metabolites of SSADH deficiency directly induce impairment of energy metabolism.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Brain / enzymology*
  • Brain / physiopathology
  • Brain Diseases, Metabolic, Inborn / enzymology*
  • Brain Diseases, Metabolic, Inborn / genetics
  • Brain Diseases, Metabolic, Inborn / physiopathology
  • Citric Acid Cycle / genetics
  • Disease Models, Animal
  • Electron Transport / genetics
  • Energy Metabolism / drug effects
  • Energy Metabolism / genetics
  • Glutathione / metabolism
  • Mice
  • Mice, Knockout
  • Mitochondria / enzymology*
  • Mitochondria / genetics
  • Mitochondrial Diseases / enzymology*
  • Mitochondrial Diseases / genetics
  • Mitochondrial Diseases / physiopathology
  • Oxidative Stress / genetics
  • Sodium Oxybate / metabolism
  • Sodium Oxybate / pharmacology
  • Subcellular Fractions
  • Succinate-Semialdehyde Dehydrogenase / deficiency*
  • Succinate-Semialdehyde Dehydrogenase / genetics
  • gamma-Aminobutyric Acid / analogs & derivatives
  • gamma-Aminobutyric Acid / metabolism
  • gamma-Aminobutyric Acid / pharmacology


  • gamma-Aminobutyric Acid
  • Sodium Oxybate
  • Aldh5a1 protein, mouse
  • Aldh5a1 protein, rat
  • Succinate-Semialdehyde Dehydrogenase
  • Glutathione
  • succinic semialdehyde